General Analysis of Uplink Group-Orthogonal MC-CDMA systems

Group-orthogonal multicarrier code-division multiple access (GO-MC-CDMA) has been proposed as a multiplexing technique for the uplink segment of wireless systems. The distinctive feature of GO-MC-CDMA with respect to MC-CDMA is that users do not employ all the available subcarriers, instead, they are collected in orthogonal groups with each group functioning as an independent MC-CDMA system. When distributing users among groups, and in order to simplify network management and to increase system flexibility, it is important to allow users in the same group to employ different modulation formats and/or power constraints. This paper generalizes previous analyses of maximum likelihood (ML) multiuser detection (MUD) in GO-MC-CDMA to the case where, due to QoS requirements, users in the same group employ different modulation formats and/or receive different power levels. Simulations results using realistic parameters over an ETSI BRAN channel model are presented which serve to validate the analytical results.